Noise-cancelling AirPod Pro

The recently launched Apple AirPod Pro presents a wonderful opportunity to relate an A-level concept to a real-world example - how noise-cancelling earphones work.

Apple's website explained it in layman terms that seem to make sense. Let your students attempt to do a better job of explaining how destructive interference of waves is applied.

I probably won't spend SGD379 on it though.

Micro:bit Line-Following Robot

I was looking for an extension to the Micro:bit Go set that I bought a while back and came across a robot set that is currently on sale. This set comes with most of the sensors a typical line following or obstacle avoiding robot needs. Currently, it is being sold at a fraction of the price of other similar Micro:bit robots, and is far cheaper than sets such as the Lego EV3.

After unpacking it earlier this evening after work, I managed to put together the parts by following the instructions, which were quite clear.

  1. Micro:bit Go (S$30 on Lazada)
  2. Yahboom Micro:bit Robot (selling for S$49.68 only at Lazada)
Before assembly
Microbit Line Following Robot
Microbit Line Following Robot

To program the robot using Micro:bit's Makecode, which is a block programming interface that is very similar to Scratch, you will need to download the Yahboom blocks by selecting Extensions from the Advanced menu.

Enter the following URL into the search bar: https://github.com/lzty634158/yahboom_mbit_en

You will then see the library of new blocks including those meant for the robot below:

A few simple lines of code are all that is needed for the light sensors to keep tracking a black line by turning whenever one of the sensors detect white while the other detects black.

After programming the robot, download the hex file into the Microbit and the robot is good to go.

one-north Festival 2019

https://www.seriouslyscience.sg/one-north-Festival/Overview

Happening now from 13-14 Sept 2019 at one-north.

My colleagues and I took the opportunity to visit the exhibitions during lunch time today. I learnt about 3M's solar films and retroreflection material, I^2R's speech-to-text recognition app with code switching capabilities (i.e. the app is able to transcribe English-Chinese mixed sentences) and cell-based prawn meat from https://shiokmeats.com/, among other things.

There was also an informative booth on Project Wolbachia (where male aedes mosquitoes infected with Wolbachia bacteria are released into the wild to control the population). I learnt that they could separate the male from the females at the pupal stage because male pupals are larger and got to stick my hand in a box full of male Wolbachia-Aedes mosquitoes.

Very hands-on booth on Project Wolbachia.
Looking forward to a future where meat is grown in labs so as to reduce animal suffering

Do check out the apps developed by the Bioinformatics Institute that can be used for science experiments or related applications.

Iconic Voices from MIT: Opening a New Window into the Universe with Dr Nergis Mavalvala

This is a free public lecture by Dr Nergis Mavalvala (an astrophysicist from MIT) on how her team detected gravitational waves generated from colliding black holes and neutron stars at the Laser Interferometer Gravitational-wave Observatory (LIGO).  Held on this coming Friday 26 Jul 2019 from 5 to 6 pm, the venue is at the Singapore University of Technology and Design (SUTD)'s Auditorium, along 8 Somapah Road, Singapore 487372.

Click here to sign up.

Phase Difference GeoGebra Apps

I created a series of GeoGebra apps for the JC topics of Waves and Superposition, mainly on the concept of Phase Difference. The sizes of these GeoGebra apps are optimised for embedding into SLS. When I have time, I will create detailed instructions on how to create such apps. Meanwhile, feel free to use them.

Instructions on how to embed the apps into SLS can be found at this staging environment of the SLS user guide.

Phase difference between two particles on a progressive wave. Move the particles along the wave to see the value.

Phase difference between two particles on a stationary wave. Move the particles along the wave to observe how their velocities are different or similar.

Observe velocity vectors of multiple particles on a progressive wave.

Javascript Game to Learn How to Count Money

Trying to brush up my Javascript skills after being inspired by one of the senior specialists in ETD, I created this simple Javascript Game to teach kids how to count money using Singapore coins.

To play this game, click or press the "Play Button". Click on the coins to make up the targeted amount. Be careful as the coins will move over one another.

This is meant for children entering primary one soon so that they can learn how to pay for food at the canteen.

To insert this into SLS, download the zipped file here and upload as a media object.

GeoGebra in SLS

Useful Links for Learning about using GeoGebra in SLS.

  1. update on 2 Jul 2019: The SLS lesson shared during IPSG 2019 can now be found in the SLS Community Gallery.
  2. Join the local community of GeoGebra users at: https://www.geogebra.org/group/stream/id/VFX2EG8xa
  3. GeoGebra tutorials at: https://www.geogebra.org/m/Ebm5wBW5  (Start with Geometry and Functions & Graphing)
  4. GeoGebra apps curated for A-level Physics: https://www.geogebra.org/m/dgedzmz3
  5. GeoGebra apps curated for O-level Physics: https://www.geogebra.org/m/z5nfs8qd
  6. IPSG Poster on "An SLS Learning Experience with GeoGebra Apps on the First Law of Thermodynamics"
  7. Instructions on how to embed GeoGebra into SLS.
  8. Let us know if you have used or adapted the SLS lesson, or if you have ideas for new GeoGebra apps in the comment section below.

Idealized Stirling Cycle

I created a new GeoGebra app based on an ideal Stirling Cycle (A. Romanelli Alternative thermodynamic cycle for the Stirling machine, American Journal of Physics 85, 926 (2017)) which includes two isothermal and two isochoric processes. The Stirling engine is a very good example to apply the First Law of Thermodynamics to, as the amount of gas is fixed so the macro-variables are only pressure, temperature and volume. Simplifying the cycle makes it even easier for first time learners to understand how the engine works.

For those who prefer to be impressed by an actual working model, it can be bought for less than S$30 on Lazada. All you need for it to run is a little hot water or some ice. Here's a video of the one I bought:

The parts of the Stirling engine are labelled here:
How a Stirling Engine works

My simulation may not look identical to the engine shown but it does have the same power piston (to do work on the flywheel) and displacer piston (to shunt the air to and fro for more efficient heat exchange).

Geogebra link: https://www.geogebra.org/m/pbnw2yas